DE1929370A1 - Incinerator - Google Patents

Description

The Minister of Technology in the Government of Her majestically ^4: Queen of the United Kingdoms of Great Britain and Northern Ireland, Millbank Tower, Millbank, London SWl, England

Verb burn institution

The invention relates to combustion devices in which a flame stabilization zone within a rapid gas flow is achieved in that the boundary layer of a body arranged in this gas flow flow is replaced accordingly.

In the case of turbine jet engines for aircraft, one can known to generate additional thrust in that

9088 SO / 0987

you also burn fuel in an afterburner. Use in such devices is ;; ince _lan: in which to obtain stable flame ~ eui fixed baffles which staoile at their drain box turbulence zones or Rückströmun ^ szonen he ^ eu ^ s saying. Such baffles, however, represent an undesirable flow resistance during the periods during which the afterburner is not in operation The extraordinary simplicity of this structure evidently allows certain disadvantages to recede. By setting the two legs of the Y-profile to an included angle of about 45 ° or, depending on the flow velocity, a little less, a reasonable compromise between flow resistance and creation of a suitable backflow zone can be achieved.

Nevertheless, the baffle resistance can assume critical values if the entire available high burner - energy is used. Furthermore, a sewing system is very desirable, which while not in use has a low pressure drop, provided that the disadvantages arising for other reasons are not too severe are.

'- 2 - SAD ORIGINAL

908850/0987

Through the -, find us the task should be solved, in the case of combustion devices of the type mentioned at the outset, adequate flame stabilization and at the same time to achieve the lowest possible pressure loss without doing this other drawbacks to nuts.

In the sense of solving this problem, a combustion device is according to the invention by at least one element arranged in a gas flow duct, furthermore by a flow divider arranged at a distance from this element and by means for any influencing the boundary layer flow present on the outer surface of said element in such a way that at least part of the main flow of the gas flow channel deflected and a Kach flow is generated with a stable turbulence zone, characterized.

Preferably, according to the invention, two of these are mentioned. Elements provided and spaced apart from one another ^ " and preferably the flow divider is located between these two elements.

In a preferred embodiment of the invention Combustion equipment are the elements mentioned and the flow divider is arranged as an annular arrangement concentrically to one another.

- _Λ · ό »·: υ ^ 6 _ 3 _ -

BAD OftiQlHAL.

909850/0987

An embodiment of a combustion unit according to the invention will now be described with reference to the accompanying drawing / in which a part of an afterburner duct with an in this arranged flame holding device according to the invention is shown.

The afterburner duct shown schematically in the drawing has a cylindrical housing 1, which extends between a turbine outlet, not shown, and a thrust nozzle, also not shown, the Direction of the gas flow indicated by arrows runs from left to right with reference to the drawing. Within In this channel 1, two annularly extending tubes 2,> and an annular flow divider 4 provided between these two tubes, are arranged concentrically to one another. The flow divider 4 has a ring, for example wedge-shaped in cross section, the wedge tip of which is opposite to the Direction of flow somewhat over the leading edge of the profile of the two tubes 2 and> protrudes and its narrow side lies approximately in the plane of the pipe centers.

In the rear, inner quadrant of the tube 2 with respect to the channel axis and the direction of flow through this channel are two rows running in the direction of the tube , arranged at a small distance from one another, radially drilled

909850/09 * 7

• Passages 5, 6 formed, the two rows of openings with reference to the pipe axis under one Angle of about 30 ° to each other are arranged. In the same Way are in the rear, outer quadrant of the tube 3 in two rows running in the direction of the tube openings 7 and 8 drilled so that the openings 5, 6 and 7, 8 formed in the two tubes 2 and 3 on each other opposite sides of the flow path formed between these two tubes are arranged.

Under normal operating conditions, the pipes around which the gas flow in the afterburner duct 1 flows and 3 and the flow divider 4 have little disturbance this gas flow, as shown in the lower part of the drawing. If afterburning is required, the inside of pipes 2 and 3 is subjected to negative pressure, whereby the boundary layer via the openings 5, 6, 7 and 8 withdrawn from the gas flow flowing over these pipes | becomes, which has the consequence that the gas flow on the outer surfaces of those pipe quadrants that are downstream with respect to the normal boundary layer separation point, whereby this gas flow is deflected and a turbulence is created * which is shown in the upper part of the drawing shown way stable recirculation zones or backflow zones with the flow divider preventing small flow diffusion. Upstream of the pipes 2,

^ R- ^: - - ;; ■ ■:> 9 0 9 8 5 0/0987

fuel injected into the afterburner duct 1 can Ignited in a known manner, the afterburner flame thus ignited remains in the return flow zone for so long by itself, like the gas flow of the Nachbrennerkanal.es is deflected due to the aforementioned suction "or under-pressure effect.

A control or regulation of the boundary layer flow can also be achieved in that gas or air flows are blown over the outer surfaces of the tubes 2 and 3 via which the above-mentioned negative pressure came into effect in the embodiment described above, for whatever purpose in the pipes 2 and 3, instead of the pipe openings 5, 6, 7 and δ, narrow slots extending in the direction of the pipe can be formed at the same points. With the same control flow rate, the losses that occur when the suction or negative pressure effect mentioned is applied are greater than the losses that occur in the embodiment to be described, in which gas is passed through the pipe openings due to the lower pressures and the consequent higher flow velocities. or air is expelled. This advantage is, however, at least partly offset by the energy for compressing the tube about ^the: is necessary openings in the augmenter duct 1 to be ejected air while the negative pressure or suction of the first-mentioned embodiment of the invention -leiefit

ORIGINAL BATHROOM - 6 -

909850/0987

can be achieved by connecting the pipes to areas of lower pressure of the engine.

A side effect of blowing in air is that the strength of the mixture is weakened in the backflow zone will. On the other hand, however, when using the mentioned negative pressure or suction effect together with the withdrawn air of the boundary layer flow Fuel also withdrawn. ^

The achievable cross section of the backflow zone corresponds approximately to the total cross section of the flame holding device, ie the distance between the radially innermost point of the tube 3 and the radially outermost point of the tube 2, as shown in the drawing. This backflow area corresponds to the reverse flow cross section achievable with a V-shaped baffle of the same radial width, but with such a V-shaped baffle the flow resistance of the free flow is approximately 1.5 times greater. In addition, the device according to the invention with reference to the known baffle clogs the gas flow channel 1 only about half, since the device according to the invention is halved, whereby devices that can occupy up to 30% of the cross section of the gas flow channel 1, according to the invention result in a loss coefficient of the gas flow channel that is only about

8A0 0RK3IMAL

909850/0987

two thirds as large as the loss coefficient that can be achieved with a comparable baffle of the type mentioned, whereby the pressure loss achievable according to the invention,

• when the afterburner is not in use, only about two

• Third as large as the pressure loss resulting from the use of a conventional baffle.

The person skilled in the art will of course find further information on the basis of the description, the patent claims and the drawing Modifications within the scope of the invention. For example, the said tubes can be two in parallel be mutually arranged tubes, which transversely through the gas flow channel 1, in which case the flow divider is also a straight line, between the two parallel tubes arranged element. Depending on the embodiment, these tubes can in turn either be acted upon with negative pressure or with excess pressure, see above that either gas is withdrawn from the gas duct or a gas stream is blown in through the pipes.

If necessary, a large number of such pairs of pipes can be used over the entire cross section of the gas flow channel 1 be arranged.

In some cases it can also be sufficient if only a single tube and one spaced apart from it

909850/0997

. Flow dividers can be used.

Instead of a circular cross section, the ^N tubes can of course also have a different cross section, by means of which the resistance exerted by these tubes on the free gas flow is reduced. Notwithstanding this, the pipes can also have a drag-reducing cladding.

It goes without saying that space-holding devices according to the invention of the type described above are not limited to their use in afterburners, but can also be used, for example, in bypass ducts of turbo blowers Find application where it is desired through the fuel combustion in these bypass channels intermittently generate additional energy.

909850/0987

Claims (9)

Claims \ \ .J Combustion device, characterized by at least one element (2, 3) arranged in a gas flow channel (1), further by a flow divider (4) arranged at a distance from this element and by means (to 5, 6, 7, 8) for any influencing of the boundary layer flow present on the outer surface of said element in such a way that at least part of the main flow of the gas flow channel is deflected and a post flow is generated with a stable turbulence zone. 2. Combustion device according to claim 1, characterized in that two of said elements (2, 3) are provided and arranged at a distance from one another, that further both elements in the manner mentioned each have means for influencing their boundary layer flow and that der ^ tr ^ murigstetlei? - (Al__zwi see these two elements is arranged. '------- 3. Combustion device according to claim 1 or 2, characterized in that the said element or elements each have the shape of tubes (2, J5) or such tubes have that these tubes also have openings (5, 6, 7, 8) leading out of them and that the interior of the or the pipes with negative pressure as a means of influencing the - 10 - 909850/0987 Boundary layer flow can be acted upon. 4. Combustion device according to claim 2 or 3, characterized in that two annularly extending, concentrically arranged pipes (2, 3) and eirv between them, arranged flow divider (4) are provided and that said pipe openings with respect to the channel flow in the rear opposite tube quadrant on both sides of the one formed between the two tubes Flow path lie. 5. Combustion device according to claim 4, characterized in that in each tube (2, 3) two in the direction of the tube running rows of openings (5, 6, 7 / -8.) are formed. . 6. Combustion device according to claim 5, characterized in that the two rows of openings of the individual r- ^ önre ~ ^ 27 ~ 3) with the axis of the respectively associated Include an angle of about 30 ° in the pipe transverse plane. 7. Combustion device according to claim 2, characterized characterized in that said two elements have the shape of pipes (2, 3) have or have such pipes that also rearward with respect to the channel flow - 11 - 90985 " Al on both sides of the flow path formed between the two tubes opposite one another Pipe quadrants running in the direction of the pipe, narrow passage slots are formed and that from the passage slots out gas, for example air, as a means of influencing the boundary layer flows over the outer surfaces the pipes can be ejected. 8. Combustion device according to claim 7 * thereby characterized in that each tube (2, J5) has two rows of passage slots has and that the two rows of slots with the axis of the associated pipe in the pipe transverse plane include an angle of about 50 °. 9. Combustion device according to one of claims to 8, characterized in that the flow divider (4) is approximately .wedge-shaped in cross-section and is arranged in such a way that the wedge tip is upstream with respect to the channel flow is directed. - 12 - 909850/0987